Is drinking water after dinner a safe. Or is it harmful to stomach/digestion. I tend to drink 1 litre of warm water after my dinner. Is it safe.

Yes. it is safe to drink water after dinner. Just don't overdo it. Digestion will not be affected. You may just go urinate a lot. .
Water. Very safe and helps with digestion. Keep it up and stay healthy.
Water. I don't see why it wouldn't be safe. You probably do get back a few times a night to urinate though...